One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10)(11,18)(12,16)(13,15)(14,19)(17,21)(20,22)(23,24)(25,26,30,33,31,28,29,38)(27,32,37,39,35,34,36,40)(2,5)(3,7)(9,11)(10,14)(12,19)(13,20)(15,23)(16,18)(17,22)(21,24)(25,27,30,37,31,35,29,36)(26,32,33,39,28,34,38,40)(1,3,4,7)(2,6,5,8)(10,15)(11,19)(13,21)(14,22)(16,17)(18,23)(25,28,31,26)(27,34,35,32)(29,33,30,38)(36,39,37,40)(2,5)(6,8)(10,16)(11,19)(15,17)(20,24)(26,28)(27,35)(33,38)(36,37) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.